1. Field of the Invention
The invention generally relates to a multi-band antenna and specifically to such an antenna integrated in a window. The invention also relates to an antenna for use on multiple cellular telephone bands.
2. Description of the Related Art
Antennas are commonly integrated in vehicle windows to reduce and/or negate the need for vertical rod antennas (e.g., mast or whip antennas) that project from various surfaces of the vehicle. By utilizing antennas integrated in windows, vehicle manufacturers obtain aesthetically pleasing and streamlined vehicle exteriors as well as reduced wind resistance. Unfortunately, performance of these window integrated antennas has often been deficient. Furthermore, placement of these antennas on glass often obstructs the view of a driver of the vehicle.
An antenna suitable for receiving and transmitting on cellular telephone bands is disclosed in U.S. Pat. No. 4,914,447 (the '447 patent). The antenna of the '447 patent includes a plurality of conductive strip segments arranged in a “U-shape” and an “inverted L-shape” connected to the “U-shape”. This antenna functions in a cellular telephone band of 860 MHz to 940 MHz. Unfortunately, the antenna does not perform in other cellular telephone bands.
U.S. Pat. No. 4,072,954 (the '954 patent) discloses a dual-band antenna. The antenna is formed of conductive strip segments disposed on a window. The conductive strip segments form a pair of dipole legs, with each leg forming an open loop. The conductive strip segments also form a vertical section disposed between the dipole legs. The antenna of the '954 patent operates primarily in the AM/FM broadcast frequency ranges, and not in the cellular telephone frequency ranges. Furthermore, the antenna of the '954 patent occupies a significant area on the window, thus obstructing the view of the driver.
There remains an opportunity for a dual-band antenna, primarily for cellular telephone use, that may be integrated with a window without significantly obstructing the view of the driver.